[PHP] In_array Help

Hello, I'm currently making a user system with a navigation which requries different ranks, such as news (rank 3) events (rank 4)

but the prob is you could just be a events manager and not need news so > is out of the question.

So the ranking system in the database look like this

3|4|5 == admin
3 = news
3|4 = news and events and so on..

Code:

PHP Code:

---

<?
// _base.php
function allowrank($rank,$catrank)
{
        $tmp = explode('|', $rank);
        if(in_array($catrank,$tmp))
        {
            return true;
        }
        else
        {
            return false;
        }
}



// navigation.php 


$sql = mysql_query("SELECT * FROM navigation WHERE main='1' ORDER by catid");
    while($row = mysql_fetch_assoc($sql)){ $i++; 
        $sql2 = mysql_query("SELECT * FROM navigation WHERE main='0' AND catid='".$row['catid']."'");
        if(allowrank($rank,$row['minrank'])) 
        {
            $rank = 0;    
        }
        else
        {
            $ranks = $rank;
        }
        if($ranks != $rank)
        {
    ?>
                
                <div class="<?php echo $row['div']; ?>" onclick="SwitchMenu('sub<?php echo $i; ?>')"></div>
                <span class="submenu" id="sub<?php echo $i; ?>">
                <?php while($row = mysql_fetch_assoc($sql2)){ 
                    if($_GET['page'] == $row['link']){ ?>            
                    <b><a href="./?page=<?php echo $row['link']; ?>"><?php echo $row['catname']; ?></a></b><?php echo space(1); ?>
                    <? }else{ ?>
                    <a href="./?page=<?php echo $row['link']; ?>"><?php echo $row['catname']; ?></a><?php echo space(1); ?>
                <? }} ?>
                </span>            
    <? }} ?>

---

Btw these are snipets of coding added together.

I've never used in_array before, and I'm not 100% sure how to use it...

Many thanks, James.

in_array() simply is what it says that it is: Is something in a array

For example:

PHP Code:

---

$array = array('a', 'b', 'c');
if(in_array('d', $array)){
echo 'We have d in our array'; // Will never be printed out, becuase there is no d in our array
}
if(in_array('a', $array)){
echo 'We have a in our array'; // Will be printed out becuase a is a value in our array
} 


---

What you should be looking at is bitmasks - much, much faster and shorter. Consider the binary representations of your levels:

Code:

---

1  = 0001
2  = 0010
4  = 0100
8  = 1000

---

Now say you wish to grand someone rank 1 and 4:

PHP Code:

---

$rank = 1 | 4; // Set all bits that are on in 1 or 4.

echo $rank; // Outputs 5, which is 0101 in binary 


---

It really is that easy! Also check out the page on bitwise operators in the manual.

The beauty is, you can also do this already in your SQL query:

Code:

---

SELECT  `username`
FROM    `accounts`
WHERE  (`accessMask` & 4)

---

(This selects someone who will at least have access mask 4).

Little more complicated: someone who is both an access mask 4 and mask 2:

Code:

---

SELECT  `username`
FROM    `accounts`
WHERE  (`accessMask` & (4 | 2))

---

Or the other way around, someone who does not have access right 8:

Code:

---

SELECT  `username`
FROM    `accounts`
WHERE  ((`accessMask` ^ 8) & 8)

---

The adventage over what you are doing is that you can suffice with a single bitwise operation, which is much, much faster than several string comparisons. Additionally, you can simply enforce access rights directly from your database instead of having a PHP script parse them.

On a sidenote: for added readability you should define the various access masks as a class constant:

PHP Code:

---

class Login {
  const   ACCESS_READ   = 1;
  const   ACCESS_NEWS   = 2;
  const   ACCESS_ADMIN  = 4;
  
  public function __construct () {
    $userMask = self::ACCESS_READ | self::ACCESS_NEWS;
  }
} 


---

Grr. Frag took the answer I was going to provide. Bitfields would be much more appropriate for this type of thing.

Quote:

---

Originally Posted by FragFrog

What you should be looking at is bitmasks - much, much faster and shorter. Consider the binary representations of your levels:

Code:

---

1  = 0001
2  = 0010
4  = 0100
8  = 1000

---

Now say you wish to grand someone rank 1 and 4:

PHP Code:

---

$rank = 1 | 4; // Set all bits that are on in 1 or 4.

echo $rank; // Outputs 5, which is 0101 in binary 


---

It really is that easy! Also check out the page on bitwise operators in the manual.

The beauty is, you can also do this already in your SQL query:

Code:

---

SELECT  `username`
FROM    `accounts`
WHERE  (`accessMask` & 4)

---

(This selects someone who will at least have access mask 4).

Little more complicated: someone who is both an access mask 4 and mask 2:

Code:

---

SELECT  `username`
FROM    `accounts`
WHERE  (`accessMask` & (4 | 2))

---

Or the other way around, someone who does not have access right 8:

Code:

---

SELECT  `username`
FROM    `accounts`
WHERE  ((`accessMask` ^ 8) & 8)

---

The adventage over what you are doing is that you can suffice with a single bitwise operation, which is much, much faster than several string comparisons. Additionally, you can simply enforce access rights directly from your database instead of having a PHP script parse them.

On a sidenote: for added readability you should define the various access masks as a class constant:

PHP Code:

---

class Login {
  const   ACCESS_READ   = 1;
  const   ACCESS_NEWS   = 2;
  const   ACCESS_ADMIN  = 4;
  
  public function __construct () {
    $userMask = self::ACCESS_READ | self::ACCESS_NEWS;
  }
} 


---

---

Sorry, I really don't understand it, could you give me indepth theory

I have added some examples to my post about this, these should make it a bit more clear.

Keep in mind that bitwise operations can be a bit confusing at first - I know they were for me. You should be able to see the logic behind them fairly quickly though if you just fiddle around with them for a bit.

How do i make a thread?

Sorry i posted this on your thread btw..

No mean replies?

Im new, Thanks.